This project seeks to determine if the fetus of the streptozotocin-treated pregnant rhesus monkey will withstand a chronic surgical preparation and be a good subject for study of the role of chronic moderate hyperglycemia in accentuating fetal metabolic acidosis and brain damage secondary to hypoxia. There is recent preliminary evidence in sheep and monkeys relating blood glucose concentrations to the degree of lactic acidosis and fetal distress in hypoxic animals. The near-term pregnant rhesus monkey has been chosen as the model for study due to the similarity of its fetal-placental metabolism to human pregnancy. Pregnant animals of 40-60 days gestation will be treated with streptozotocin to produce glucose in tolerance and moderate fasting hyperglycemia. A surgical preparation for chronic catheterization of the non-exteriorized fetus will be utilized which has a 76% rate of success in previous experiments. Three days after the initial surgery, maternal and fetal hypoxia will be produced in a group of normal and streptozotocin-treated monkeys by limiting maternal FiO2 to 0.09. We will measure changes in fetal heart rate and arterial pressure, blood gasses, pH, and lactic and ketone acids. After the experimental period, we will anesthetize the gravidas and deliver the fetuses by cesarean section. Their brains will be removed for pathologic examination and measurement of cerebral tissue lactic concentration. This study should provide information relevant to fetal distress in diabetic pregnancy and perhaps to management in parturition in other high-risk pregnancies.